New advanced nuclear reactors can operate without using any water

State Rep. Michael Carbone and Rep. Justin Wilmeth. Image via azleg.gov.

In a state where every drop counts, concerns about the water demands of new power plants are reasonable. Arizona has endured more than two decades of drought. Reservoirs on the Colorado River are at historic lows, and the state has renewed an emergency drought declaration every year since 1999. Any proposal to build a new thermal electric power plant naturally raises a critical question: Where will it get its water—and how much will it use?

Arizona has long recognized the link between energy planning and water security. In 2010, the Arizona Corporation Commission revised its Integrated Resource Planning rules to require utilities to report the annual water use of their facilities and to prioritize dry-cooling options when available and cost-effective. That decision reflected our clear commitment to aligning energy policy with long-term water realities.

No form of energy is entirely without impact. A single utility-scale solar facility in Arizona can use up to 43 acre-feet of water per year simply to keep panels free of dust. In a desert state, that amount matters.

When it comes to nuclear power, however, Arizona has already shown that innovation is possible. For more than 30 years, the Palo Verde Nuclear Generating Station—located just 50 miles west of Phoenix—has operated as the only nuclear power plant in the world not built near a large body of water. Rather than diverting water from rivers or aquifers, Palo Verde relies on recycled wastewater to cool its reactors and generate electricity.

That achievement proved nuclear can work in the desert. More importantly, it established a foundation of water conservation that the next generation of reactors is now poised to surpass.

For advanced reactors currently being designed, future conservation does not come from changing the source of water—it comes from eliminating the need for water altogether. Traditional nuclear plants exist for one primary purpose: to boil water. The conventional light-water reactor may ultimately be remembered as the most technologically complex way ever devised to turn water into steam. Even most fusion concepts—the so-called “holy grail” of energy—are designed around the same steam-based model.

That era is ending.

A new generation of advanced nuclear reactors is being developed that abandons high-pressure steam entirely, generating clean, reliable, and abundant electricity without water, cooling towers, or wells.

Oklo’s Aurora reactor, backed by the U.S. Department of Energy and the U.S. Air Force, is a 1.5-megawatt fission microreactor that uses metallic fuel and heat pipes to produce electricity without any water.

Westinghouse’s eVinci reactor is a five-megawatt solid-state fission system that relies on heat pipes and a closed Brayton cycle—again, requiring no water.

Ultra Safe Nuclear Corporation’s Micro Modular Reactor uses molten salt fuel and helium gas to convert heat into electricity through dry-cooled turbines, eliminating water use entirely. A demonstration unit is under construction in Canada, with U.S. deployments planned.

On the fusion side, Helion Energy’s Orion reactor, backed by Microsoft and Nucor, is designed to generate electricity directly from plasma using electromagnetic pulses—bypassing steam and water altogether.

TAE Technologies’ Da Vinci reactor pursues aneutronic hydrogen–boron fusion, converting charged particles directly into electricity without using water at any stage of the process.

Together, these designs match nuclear’s technological sophistication with equally advanced outcomes: electricity produced directly from heat or plasma, without steam cycles, cooling towers, or water withdrawals. They reject the outdated assumption that nuclear power must be water-intensive and offer a solution uniquely suited to the realities of the Desert Southwest.

As Arizona confronts the combined pressures of limited water supplies and future growth, difficult decisions will need to be made about which industries belong here. But if the state is willing to support water-intensive sectors like semiconductor fabrication and advanced manufacturing, it should be more than willing to support carbon-free nuclear technologies that do not use a single drop of water. If water is the concern, these reactors should be welcomed with open arms.

For Arizona, advanced nuclear offers something we have never had before: clean, reliable, zero-emissions power with zero water use. Not even solar can make that claim.

These technologies are real. They are backed by serious public and private investment. And they are ready to move forward. When it comes to advanced nuclear, the question of water no longer applies. It is time to stop treating water as an obstacle—and start supporting the technologies that secure Arizona’s energy future.

Michael Carbone is a Republican member of the Arizona House of Representatives representing Legislative District 25 and serves as House Majority Leader. Follow him on X at @MichaelCarbone.Justin Wilmeth is a Republican member of the Arizona House of Representatives representing Legislative District 2 in North Phoenix and serves as Chairman of the House Committee on Artificial Intelligence & Innovation. Follow him on X at @JustinWilmethAZ.